When using Apple's iBooks Author you can use the following solution to embed GeoGebra applets as widgets without an internet connection.
An iBook Widget is a GeoGebra Widget for iBooks Author that does not contain the core GeoGebra Application but rather links to another Widget that contains the core instead. The core widget does take ~10 MB of space when zipped, the widgets themselves don't take more than about 100KB each, no matter how many of them are used. You only have to insert the core once in your iBook. Once installed, you download your GeoGebra file .zip, you extract it (double click on it), and you go on iBooks Author and insert it as an HTML5 Widget... (The same way you installed the Core, explained here).
Setup the Core
Prepare the core
The core widget can be downloaded here (~10 MB):
The core widget has to be unzipped afterwards. Usually it is sufficient to double-click the downloaded file.
Load the core
In the iBooks Author application, the core widget can easily be inserted as usual HTML5 widget.
Hide the core
Unfortunately the size of a widget cannot be less than 100x100px. Therefore the core widget has to be hidden somehow else. One solution might be to move it to the invisible area outside the page.